Bluetooth: sco: new getsockopt options BT_SNDMTU/BT_RCVMTU

This patch defines new getsockopt options BT_SNDMTU/BT_RCVMTU
for SCO socket to be compatible with other bluetooth sockets.
These new options return the same value as option SCO_OPTIONS
which is already present on existing kernels.

Signed-off-by: Joseph Hwang <josephsih@chromium.org>
Reviewed-by: Alain Michaud <alainm@chromium.org>
Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Reviewed-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/sco.c

@@ -1001,6 +1001,12 @@ static int sco_sock_getsockopt(struct socket *sock, int level, int optname,
 			err = -EFAULT;
 		break;
 
+	case BT_SNDMTU:
+	case BT_RCVMTU:
+		if (put_user(sco_pi(sk)->conn->mtu, (u32 __user *)optval))
+			err = -EFAULT;
+		break;
+
 	default:
 		err = -ENOPROTOOPT;
 		break;